1. Objective: Students will be able to use percents to calculate parts needed
Students will be able to use systems of equations to solve mixture problems
A.REI.06
Reasoning With Equations And Inequalities
Solve Systems Of Equations
Solve systems of linear equations exactly and approximately (e.g., with graphs), focusing on pairs of linear equations in two variables.

2. Building Today’s Roads
Objective: Students will be able to use percents to calculate parts needed
Students will be able to use systems of equations to solve mixture problems
A.REI.06
Reasoning With Equations And Inequalities
Solve Systems Of Equations
Solve systems of linear equations exactly and approximately (e.g., with graphs), focusing on pairs of linear equations in two variables.
Building Today’s Roads
Asphalt Mixture
Asphalt Plant Tour
Beyond Roads

3. What do you already know about asphalt?
List at least three things.

4. Quality Control Sieves to test sizes of rock
Asphalt gets testing for % oil and air voids
Single sieves – each sieve has different size mesh

5. Knife River Corporation www.kniferiver.com
Asphalt Tanks
Rock Equipment
Moving Rock

6. Let’s learn a little more about asphalt
Go to the following website – then follow instructions on next page

7. Instructions for reading
Group 1-
The Materials
Group 2-
What are aggregates?
Group 3-
What is liquid asphalt?
Group 4-
What are the specifications?
Group 5- How are asphalt mixtures made?
Group 6- What is warm mix asphalt?
Count off by 7
Click on “What is Asphalt?”
On the right there are 7 sections – your number will correspond with the section you will read
Read and takes notes (you will need to write at least four facts about your reading) (5 minutes)
Become an expert – meet with the people with the same number as yourself. Discuss your notes, together come up with what you want to share.
Find 6 people with a different number than you have, each person share your expertise with the group
Group 7 –
Fast facts

8. 1. 2. 3. 4. 5. 6. 7.

9. Let’s make asphalt!! (not really – sorry)
Asphalt Concrete – what you see on the roads
Asphalt Binder – the black goo that holds everything together
Aggregate – the rock (made of specific ratios of sizes)
Asphalt Concrete = 5%Asphalt Binder + 95% Aggregate
If we want to make 2500 lbs of asphalt concrete, how much binder and aggregate are needed?
If we want to make 450 lbs of asphalt concrete, how much binder and aggregate are needed?
If we want to make 6 tons of asphalt concrete, how much binder and aggregate are needed?
6 Tons = 2,000 x 6 = 12,000 lbs
Binder: 12,000 x .05 = 600 lbs
Aggregate: 12,000 x .95 =
11,400 lbs
Check:600 lbs+11,400 lbs = 12,000 lbs (amount of asphalt concrete)
Binder: x .05 = lbs
Aggregate: 2500 x .95 = 2735 lbs
Check: 125 lbs lbs = 2500 lbs (amount of asphalt concrete)
Binder: 450 x .05 = lbs
Aggregate: 450 x .95 = lbs
Check: 22.5 lbs lbs = 450 lbs (amount of asphalt concrete)
(not really – sorry)

10. Systems of Equations to Solve Problems
We already have two Asphalt Concrete mixes:
Mix 1: 3% Asphalt Binder
Mix 2: 8% Asphalt Binder
We want to make a 1 ton mixture that is 5% Asphalt Binder.
How much of each mix is needed?
Let x = Amount of mix 1
Let y = Amount of mix 2
x + y = 2000
.03x + .08y = .05(2000)
x = 1200 lbs of mix 1
y = 800 lbs of mix 2
Remember: 1 ton = 2000 lbs

11. Systems of Equations to Solve Problems
We already have two Asphalt Concrete mixes:
Mix 1: 2% Asphalt Binder
Mix 2: 7% Asphalt Binder
We want to make a 3.2 ton mixture that is 4% Asphalt Binder.
How much of each mix is needed?
Let x = Amount of mix 1
Let y = Amount of mix 2
x + y = 6400
.02x + .07y = .04(6400)
x = 3840 lbs of mix 1
y = 2560 lbs of mix 2
Remember: 1 ton = 2000 lbs

12. Quality Control
Link to Asphalt Mixture Volumetrics p.63, p.69 example calculations